This invention relates to a method and apparatus for detecting and locating annoying rattles, squeaks and other noises in automotive vehicles, especially while they are in a stationary parked position. It is especially suitable for use by automotive repair and service personnel.
Modern automotive vehicles, whether automobiles, SUVs, trucks or minivans, are each configured by a complex structure of under the hood machinery, framing, doors, and related devices and compartments which have a potential for problematic vibrations, raffles and squeaks. Frequently, such unwanted noises are caused by glitches in the manufacturing process or even small items like nuts, washers or pieces of metal inadvertently left in framing structures or inside panels.
To help achieve high customer satisfaction, automotive vehicle manufacturers want to eliminate rattles, squeaks and other unnecessary and undesired noises from occurring. But because these objectionable noises only occur when the vehicle is in use, they are difficult and time consuming to track down and correct.
Vehicle rattle and noise related complaints are very common at dealer manufacturers' service centers. Addressing them usually involves a trained automotive mechanic or technician test driving the vehicle. Sometimes a second mechanic rides along either in the back or trunk of the vehicle. Heating and air conditioning systems in the vehicle are usually turned off to reduce internal vehicle noise and all windows are usually shut to reduce external noise from interfering with the detection and location of rattles. These situations cause extreme discomfort to the automotive mechanics while test driving in freezing winter weather or extremely hot summer weather.
An attempt by a motor vehicle manufacturer to provide an apparatus for the identification of vibration induced noises on vehicles in a stationary test facility is described in U.S. Pat. No. 5,551,298 to Rayment, Sep. 3, 1996. A large, space consuming and expensive apparatus is disclosed comprising a means for supporting the entire vehicle on its wheels, a vibration generator (preferably hydraulically driven) for vibrating the wheel supporting means, a control means for controlling the frequency of operation of the vibration generator, a data capture means for receiving inputs for vibration induced noises, and a means for comparing the frequency at which the induced noise occurs with a set of stored data to hopefully identify the source of the vibration induced noise.
The vehicle support means of Rayment has four separate wheel supporting columns, each of which can be oscillated separately to vibrate the supported vehicle. While such a large intricate system may be beneficial at a major automotive manufacturing facility, it is just too large, intricate and expensive for the thousands of auto dealership service centers or unaffiliated auto repair shops nationwide.
In U.S. Pat. No. 5,574,226 to Reuther et al, Nov. 12, 1996, a large environmental auto test facility for testing vehicle suspension and body components is disclosed. This facility is transportable in large trailers over conventional roads and is essentially self-contained for set-up at automotive manufacturing facilities. It provides a four-posture hydraulic suspension with each hydraulic actuator independently controllable and adapted to engage one of the tires of the vehicle to be tested. The plurality of hydraulic actuators are associated with the bed of the trailer and specific seismic mass.
One purpose of Reuther et al is to make an effort to ensure new vehicles are quiet and essentially free of squeaks and rattles. However, the trailer mounted road simulator environmental test facility disclosed, while designed for use at an automotive manufacturing facility is exorbitantly expensive, too space requiring, intricate, and costly to operate for even automotive dealer service centers or independent auto repair shops.
The vibration and acoustic sound diagnostic instrument disclosed in U.S. Pat. No. 5,435,185 to Eagen, Jul. 25, 1995, is usable by professional automotive mechanics for discriminating audible vibration sound and noise from under-chassis and under-hood parts and devices having mechanical faults. It includes one or more acoustic vibration pick-up devices adapted for mounting in contact with an automotive part for detecting and converting vibratory acoustic signals and sounds into electromagnetic signals and an electronics housing conforming to be hand held. A preamplifier circuit in the housing is coupled to the acoustic vibration pick-up device and to range selector circuitry for selecting sound level ranges. A decibel meter, mounted to the housing exterior, is interconnected to the pre-amplifier for visually indicating changes and peaks in sound levels detected by the transducer microphone. Audio amplifier circuitry within the housing is interconnected to pre-amplifier circuitry for converting the electromagnetic signals into secondary acoustic signals that may be listened to by an automotive mechanic through an earphone headset electrically interconnected to the audio amplifier. A battery power supply within the housing energizes the instrument.
A disadvantage of this sound diagnostic instrument is it was designed for use during normal driving movement of the vehicle. It may, however, if extreme sound sensitivity is desirable, be used in conjunction with applicant's invention while the vehicle to be tested is in a stationary position.